Floating roof tank



J 2, 1951 J. w. ALLEN 2,536,019

FLOATING ROOF TANK Filed Nov. 5, 1945 Patented Jan. 2, 1951 UNITEDSTATES PATENT OFFICE FLOATING ROOF TANK John W. Allen, Chicago, Ill.,assignor to Chicago Bridge & IronGompany, a corporation of Illi- 3Claims. 1

This invention relates to a floating roof tank, and particularly to aseal for a floating roof tank for sealing the area between the edge ofthe roof and the inner surface of the tank shell.

Floating roof tanks for the storage of volatile liquids in which a roofis provided that floats on top of the liquid contents must have meansfor sealing the annular area between the edge of the roof and the tankshell. This is necessary in order to prevent evaporation of the tankcontents and to prevent contamination with water, dirt, and the like. Ihave invented an improved seal that is light in weight and simple toinstall, and that provides a positive sealing action between thefloating roof and the tank shell.

The new seal comprises a shoe, preferably of metal, normally pressingagainst the inner surface of the shell and removably attached to thefloating roof, and a seal section extending from the shoe to the roof.There is also provided spring means to aid in pressing the shoe againstthe shell and preferably a secondary seal that is normally held insealing contact with the tank shell. The seal achieves a positivesealing action partially by its own weight, and partially by the springmeans.

The invention will be described as related to the embodiment shown inthe accompanying drawings. Of the drawings Fig. 1 is a fragmentary planview of the floating roof tank embodying this invention; Fig. 2 is afragmentary vertical section taken through the edge of the floating roofand the adjacent portion of the tank shell; and Fig. 3 is a horizontalsection taken along line 3-3 of Fig. 2.

The tank shown in the accompanying drawings comprises a shell IE! and afloating roof H positioned therein. Between the edge of the floatingroof and the inner surface of the tank shell there is provided a sealcomprising a flexible metal shoe l2 adapted to rest flat against theshell, an annular metal cover plate 13 attached to the topof the shoe l2and held in generally horizontal position, and a flexible sealing stripl4 extending from the cover plate l3 to the top surface I5 of the roofII. There is also preferably provided a secondary seal I6 comprising alooped fabric fastened to the cover plate It and pressing against theshell I0. The flexible sealing strip l4 and secondary seal 16 arepreferably made of a fabric impregnated with a flexible imperviousmaterial that is wear-resistant.

The seal is held in place by means of vertical bars I1 adapted to beheld against the edge of behind a first bracket 24.

the floating roof and upwardly extending hanger bars 23 extendingbetween the vertical bar 11 and the shoe (2. The hanger bars 23 arerotatably fastened to the vertical bar l1 and to the shoe l2, so thatthe weight of the shoe and attached sealing members will force the shoeand the secondary seal out against the shell. Each bar I! is held inposition on the edge of the roof by means of a base member 18 which maycomprise an extending bottom edge of the roof, and each bar is heldagainst lateral movement by means of spaced guide members IS. Thevertical bars I] are removably held in place against the edge of theroof by a pin 20 passing through the top of each vertical bar I1 and thetop edge 2| of the roof. The edge. of the roof is extended above the topsurface 15 in order to provide the top portion 2L Each pin 29 is held inplace by means of a second, smaller pin 22 passing through the end.

On the top surface of the metal cover plate I3 there is provided aseries of spaced brackets 24 attached to the plate. A series of secondbrackets 25 is attached to the roof in upstanding position with eachsecond bracket 25 being immediately Extending between each first bracketand each second bracket is a threaded rod 25 loosely held within holes21 and 28 provided in the first and second brackets respectively. Therod 25 is held within the second hole 28 by means of spaced collars 29mounted on said threaded rod. The rod 26 is also provided with aflaredend ti! on the other side of the first bracket '24 to preventaccidental displacement of the rod. Mounted on the rod 26 is a threadedbase member 3| engaging the threads of the rod 26 and located betweenthe first bracket 24 and the second bracket 25. A spring 32 extends fromthe base member 3! to the first bracket 24, and this spring is held incompression substantially concentrically to the rod26.'

The secondary seal it is mounted on the metal cover plate It adjacentthe metal. shoe l2 by means of a plurality of spaced bolts 33 extendingthrough the cover plate and the edge of the seal. The top edge 34 of theshoe I2 is bent back from the shell and is fastened to the edge :35 ofthe cover plate It by means of a plurality of bolts 35 passing throughthe edge 34 of the shoe, a compression strip 31, and the edge 35 of thecover plate. The flexible sealing strip M is attached to the metalcovering plate I3 by means of a plurality of bolts 38 passing throughthe inner edge of the covering plate l3 and the top edge of the sealingstrip I l. The bottom edge of the sealing strip is fastened to the topsurface 15 of the roof by means of a plurality of hooks 39. The edge ofthe sealing strip is held by wedges 40 contacting the hooks 39 andwedging against a circular bar 4| which presses against the edge of thesealing strip I 4.

The seal described herein is light in weight and easy to install, andprovides a positive sealing action between the roof and the tank shell.The removable support for the shoe makes erection easier and maintenanceof the seal simple. The shoe !2 is held in place against the shell ii]partially by its own weight and partially by the action of the spring 32pressing the metal cover plate outwardly. The spring 32 also serves topress the secondary shell I6 against the shell. The compression of thespring may be varied by varying the distance of the threaded base member3| from the first bracket 24.

The metal shoes [2 are ordinarily made in sections ,and adjoiningsections are connected together by means of fabric strips 42 impregnatedwitha flexible impervious material. The edges of these strips are heldin place by means of hooks 43, rods 44, and wedges 45 of the same naturethose used in fastening the edge of the sealing strip 14 to the topsurface i of the roof.

Any other suitable fastening means may of course" be used. In a typicalinstallation the shoes were 9 feet long and 4 hanger bars were used,each spaced 2 feet from an end of the shoe. The 4 bars were arranged invertically aligned pairs, with each pair being substantially parallel toall the others. In order to prevent lateral movement of the seal therewere provided crossed bracing rods 45 between two laterally adjacenthanger bars 23. This bracing may be provided either on the top pair ofhanger bars, the bottom pair of hanger bars, or on both pairs.

Having described my invention as related to one embodiment of the same,it is my intention that the invention be not limited by the details ofdescription unless otherwise specified, but rather be construed broadlywithin its spirit and scope as set out in the accompanying claims.

I claim:

1. In a liquid storage tank having a floating roof and a plurality ofshoes adapted to slidably contact the inner side walls of the tank, anannular seal between the shoes and the roof, means for supporting saidshoes against the tank wall comprising a plurality of pairs ofsubstantially vertical guide members attached to the edge of thefloating roof and extending downwardly into the space between the roofand the walls beneath the annular seal, a vertical bar held between eachpair of guide members shoe supporting hangers attached to the shoe andattached to the vertical bars, and means for removably securing saidbars to theroof, said means being connected to the roof and to the barsonly at the upper edge of the roof.

2, Apparatus of the character described in claim 1 in which said annularseal comprises an annular metal cover plate attached to the top of theshoes, a secondary seal carried by the cover plate and pressing againstthe side Walls above the shoes a flexible sealing strip extending fromthe cover plate to theroof, a series of spaced brackets mounted on thecover plate, a series of second spaced brackets mounted in upstandingposition around the edge of the roof adiacent said first brackets, athreaded rod extending between each of said first brackets and each ofsaid second brackets and loosely held in said brackets, a threaded basemember engaging the threads on said rod and located between said firstand second brackets, a spring positioned around said rod and extendingfrom the base member to said first bracket, said spring being adaptedfor compression between the base member and the first bracket.

3. In a liquid storage tank having a floating roof, a plurality of shoesadapted to slidably contact the inner side walls of the tank and meansfor supporting said shoes against the side walls, sealing meanscomprising an annular metal cover plate attached to the top of the shoesand extending substantially horizontally inward toward the roof, asecondary seal carried by the cover plate and pressing against the sidewalls above the shoes, an annular flexible sealing strip extending fromthe cover plate to the roof, a series of spaced brackets mounted on thecover plate, a series of second spaced brackets mounted in upstandingposition around the edge of the roof adjacent said first brackets, athreaded rod extending between each of said first brackets and each ofsaid second brackets and loosely held in the brackets, stop means oneach rod adapted to abut the second bracket, a threaded base memberengaging the threads on said rods and located between said first andsecond brackets, a spring positioned around said rod and extending fromthe base member to said first bracket, said spring being adapted forcompression between the base member and the first bracket.

JOHN W. ALLEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,463,268 Huff July 31, 19231,574,013 Wiggins Feb. 23, 1926 1,660,021 Wiggins Feb. 21, 19281,662,225 Wiggins Mar. 13, 1928 1,668,792 Wiggins May 8, 1928 1,673,984Kuhl June 19, 1928 1,801,582 Wiggins Apr. 21, 1931 1,900,904 Berger Mar.14, 1933 1,989,624 Matter Jan. 29, 1935 FOREIGN PATENTS Number CountryDate 487,774 Great Britain June 24, 1938

